The "proper" way to get a Hydrogen track into Ardour is to connect Hydrogens output (using the Connect button in qjackctl for instance) to a track in Ardour and record it. Nothing horribly wrong with your method though...

What Paul meant was that no released version of Ardour, up til and including the 2.x series, support MIDI.
Ardour 3 will, but that's not released yet and will take a while to be finished.

As for extracting drum parts; load it into Rosegarden and mute the other tracks (assuming it's a MIDI-1 file with separate MIDI tracks. If it's a MIDI-0 track you'll have to use some script to convert it to MIDI-1 first).

and the answer should be like this: never. Ardour is ardour and if you're not happy with it, you can use something else.

To make things clear:
- jack has a transport mode that allows every client that was coded for it to become transport slaves, so all interconnected clients that understand this transport mode can be controlled by any of them (qjackctl has even a jack transport interface in its main window, just for that purpose)

- hydrogen is not yet a plugin that you can load in an instrument rack inside ardour. Whether it will happen is something that only hydrogen's devs can answer.

- hydrogen exposes jack ports so one can connect them to ardour (audio only). You can do all your sequencing in hydrogen, no need to involve ardour in the sequencing of you drum beats. You can match time changes, tempo changes in both apps. One can become the slave of the other (e.g. by making ardour the time master) and activating the jack transport mode in both apps.

- only record hydrogen's audio outputs when you are done and happy with your sequencing

The drawback is that you have to recall every app's configuration and inter-connectivity. That's something that the lash project is supposed to do for you automatically but this does not seem to emerge as THE solution. When ardour3 is out and gets cleaned of bugs, we'll see how things change. I believe more and more apps will come up with plugin versions of themselves, hydrogen being a good candidate for that, at least the sampling part.

The non unix/linux apps cited above want to be all-in-one solutions and compete between each other because this is a commercial market in a closed source environment. Ardour is following another path and has adopted the unix philopsophy for better or for worse. But this is not written in marble or gold and can always evolve in the future.

Please folks, stop this non-sense comparison with proprietary DAW systems, developed on different OSes, etc. Ardour does not aim at emulating these systems, its ambition is to be a useful tool for music producers (pro or not) and it is definitely getting there (at least for me).